Method of manufacturing a solidtype door



March 19, 1968 L. PICK 3 Filed April 27. 1964 4 4 4 m m v (II m K W m 1 IOL/ E m J n 2 HM f A M w I [W w w m L \6 A f. $4 1, n 4 6 W I 6 d A: T: L, 3 F8 5 M I Hi 8\4\ H .M I] m. 3 a 3.7.1 t 4 United States Patent 1 Claim. (Cl. 156-265) This invention relates to wooden doors and, more particularly, to solid-type doors of the type which are customarily used in commercial and institutional buildings. Such doors conventionally comprise a core which is made up of a large number of separate wooden elements, and one or more external covering sheets such as those which are known as crossbands, veneers and the like. It is most important that doors of this type be strong and rigid and resist warping in all directions, and the provision of a solid-type door having these qualities is most important.

It is well known in the art that it is very desirable to impregnate the wooden members which form the core of the door of the described type with a water repellant, or a wood preservative material, or a fire retardant material, or a combination of such materials, in order to secure the benefits of these materials. However, such impregnation has not been practical because of the fact that it is not possible to glue the external covering members, such as the crossband, to impregnated wood members. It has therefore been necessary either to forego the advantages of such impregnation or, if such impregnation is used, to resort to some means other than gluing for attaching the external covering sheets to the core members. Neither of these alternatives is desirable, and it has therefore been a matter of importance in this art to find some means or construction whereby the advantages of impregnation and the advantages of gluing may both be secured.

It has therefore been the principal object of this invention to provide a core for a solid-type door which is so constructed that the parts thereof may be impregnated with a wood preservative material or a water repellant material and which, at the same time, may be attached in the usual way to the external sheet covering member by gluing.

Description of the drawings:

FIG. 1 is a perspective view of a board from which parts of the core of a door may be made in accordance with the invention;

FIG. 2 is a perspective view of the same board after impregnation with a water repellant, wood preservative or fire retardant material;

FIG. 3 shows a plurality of strips formed from the board of FIG. 2;

FIG. 4 is a transverse sectional view taken on line 44 of FIG. 5, showing the core of a typical door constructed in accordance with the present invention, and

FIG. 5 is a plan view of one type of door core which might be constructed in accordance with my invention.

The steps to be followed in carrying out the method according to my invention are illustrated in FIGS. 1 to 4 of the drawings, and in FIG. 5 there is illustrated, in section, the core part of a solid-type door constructed in accordance with the invention.

As a first step in my invention I take a board of a wood which is suitable for use as the core member of a solid-type door, this board being shown at A in FIG. 1. A typical board suitable for this use might be 6" wide by 1 /2" thick and of a suitable length depending on the type of core construction to be used. For example, the board may be sufficiently long to extend throughout the vertical height of the door, or it may be approximately one-half 3,374,135 Patented Mar. 19, 1968 the vertical height of the door, as shown in FIG. 5, if the door construction disclosed and claimed in my co-pending application Ser. No. 100,053, now Patent No. 3,165,792, for Structure for Doors and the Like, is to be used.

The board A of suitable and desired dimensions is next impregnated, preferably under pressure, with a material having a desired beneficial effect on the wood of the board, such as a wood preservative or water repellant material, as shown at 2 in the drawings. A suitable wood preservative material is chromated zinc chloride, while a suitable water repellant material is pentachlorophenol, and a suitable fire retardant material is ureaformaldehyde in combination with ammonium phosphate. Such impregnation will cause the wood preservative or water repellant or fire retardant material, or the combination of them to penetrate a short distance into the wood of the board but, in accordance with my invention, the impregnation is not permitted to extend throughout the entire board. Thus, as shown in FIG. 2, the impregnating material fills only a zone adjacent the periphery of the board, leaving the central part thereof in its natural state, unaffected by the impregnating material.

After such impregnation the board is ripped from end to end by a saw, as shown in FIG. 3, forming a plurality of strips 4, each of which has a width equal to the designed thickness of the core which is to be made. It will be seen that each of the intermediate strips, such as strips 4a, will have impregnating material 2 over each of its opposite faces 6, and that its other opposite faces 8, along which the strips were cut from each other, are un-impregnated throughout substantially their entire areas.

The core of the door is now formed from these intermediate strips 4a by placing them in side-by-side relation with the impregnated faces 6 in face-to-face substantially abutting relation, as shown in FIG. 4, but without any attaching or connecting material between them. The facing impregnated surfaces 6 of the strips extend at substantially right angles to the general plane of the core and of the door, forming a flat core body. In this position and condition the two opposite un-impregnated edge faces 8 of each strip face outwardly to the opposite'sides of the core and, being un-irnpregnated, may be glued in the usual manner to the external covering sheet such as the crossband 10, the glue connection being shown at 12 in FIG. 4. The aligned, un-irnpregnated, co-planar surfaces 8 present practically continuous un-impregnated surfaces on the opposite side faces of the core, thus giving a very large area for glue attachment to the crossbauds 10 or other external sheet coverings. An external veneer covering 14 may be adhesively or otherwise attached to the exterior surface of each crossband 10 in accordance with usual practice.

The core structure provided by the invention may be used in the manufacture of a solid-type door of any desired construction. In FIG. 5 of the drawings I have shown the core according to the invention as used in the manufacture of a door having the construction disclosed and claimed in my aforesaid co-pending application, and reference is made to the disclosure of that application for a full description of this door construction, which therefore need not be further described here. It will be observed, however, that the strips 4 form the core of the door of FIG. 5 and are covered by the crossband 10 and the veneer 14 in forming the finished door.

It will be seen that the core construction provided by this invention permits the advantages of both impregnation and glue attachment to be realized. The facing impregnated surfaces of the core strips are not connected and the positive advantages of an expansion joint are thus provided between adjacent strips. A door having a core formed in accordance with the present invention is highly resistant to warping but is very strong and, because of the impregnation, is highly resistant to wood deterioration and moisture.

While the invention is described particularly in the specification as applied to the construction of a core formed of a relatively small number of elongated strips, it is equally applicable to the manufacture of the more conventional type of core which is formed of a relatively large number of wooden blocks of relatively small size. The application of the invention to a door of such conventional construction will be apparent and need not be described in detail here.

While I have described one form which my invention may take, and one series of steps by which it may be carried out, it will be apparent to those skilled in the art that other embodiments and series of steps, as well as modifications of those disclosed, may be made and practiced without departing in any way from the spirit or scope of the invention, for the limits of which reference must be made to the appended claim.

What is claimed is:

1. The method of manufacturing a solid-type door, which consists in first forming a core for the door by impregnating at least one wooden board to a relatively shallow depth with a material having a desired beneficial effect on the wood, then cutting the board into strips each having a width approximately equal to the designed thickness of the core, each of such strips having opposite impregnated surfaces and opposite unimpregnated surfaces, placing strips in side-by-side relation with the opposite impregnated surfaces of adjacent strips in abutting relation and with the opposite un-impregnated surfaces thereof in co-planar relation on the opposite side faces of the assembly of strips, and finally placing an exterior sheet covering member on at least one of the co-planar un-impregnated surfaces of the assembly of strips and uniting such sheet to such surfaces.

References Cited UNITED STATES PATENTS 1,394,119 10/1921 Rockwell 161-38 2,563,821 8/1951 Denig 161l60 2,869,598 1/1959 Loetscher 156-265 3,234,074 2/1966 Bryant 16136 DOUGLAS 1. DRUMMOND, Primary Examiner. 

1. THE METHOD OF MANUFACTURING A SOLID-TYPE DOOR, WHICH CONSISTS IN FIRST FORMING A CORE FOR THE DOOR BY IMPREGNATING AT LEAST ONE WOODEN BOARD TO A RELATIVELY SHALLOW DEPTH WITH A MATERIAL HAVING A DESIRED BENEFICIAL EFFECT ON THE WOOD, THEN CUTTING THE BOARD INTO STRIPS EACH HAVING A WIDTH APPROXIMATELY EQUAL TO THE DESIGNED THICKNESS OF THE CORE, EACH OF SUCH STRIPS HAVING OPPOSITE IMPREGNATED SURFACES AND OPPOSITE UNIMPREGNATED SURFACES, PLACING STRIPS IN SIDE-BY-SIDE RELATION WITH THE OPPOSITE IMPREGNATED SURFACES OF ADJACENT STRIPS IN ABUTTING RELATION AND WITH THE OPPOSITE UN-IMPREGNATED SURFACES THEREOF IN CO-PLANAR RELATION ON THE OPPOSITE SIDE FACES OF THE ASSEMBLY OF STRIPS, AND FINALLY PLACING AN EXTERIOR SHEET COVERING MEMBER ON AT LEAST ONE OF THE CO-PLANAR UN-IMPREGNATED SURFACES OF THE ASSEMBLY OF STRIPS AND UNITING SUCH SHEET TO SUCH SURFACES. 